1. Field of the Invention
The present invention relates to construction equipment, and more particularly, to a hoisting apparatus mounted on a roof parapet.
2. Description of the Related of the Art
A great variety of devices for lifting objects to the roof of a building have been developed. Typically these devices may be used to lift construction materials or equipment during roofing construction or reconstruction. In many of the new commercial buildings having flat roofing, particularly those constructed within the past ten years, a relatively tall reinforced concrete parapet wall, often 4 to 6 feet in height, defines the roof perimeter. Prior to at least one relevant building code provision implementation pertaining to roof parapets, the parapets were typically constructed at a height of 2 to 3 feet. The newer buildings, having parapet walls of 4 to 6 feet, have been constructed to satisfy OSHA requirements, and to maintain the building appearance by blocking HVAC units, and any other mechanical equipment, from street view.
The taller parapet walls make it impossible to operate a standard roof-mounted boom or roof-anchored derrick. The tallest (40-foot) ladders will only accommodate heights of 34 feet, and hauling material or equipment by ladder is dangerous. As a result, with the 4 to 6 foot parapet walls, a contractor will have to rent a standard crane, which is operator assisted, expensive and inconvenient.
Thus, a light-weight lifting device is needed that can be easily and conveniently deployed within minutes, assembled and mounted onto the upper portion of a tilt-up panel, or other steel reinforced concrete parapet, for the purpose of hoisting miscellaneous materials, equipment and tools from the ground, over the parapet, and safely onto the roof, and the instant invention fills this need.
The related art discussed below is representative of developments prior to my invention.
U.S. Pat. No. 5,341,989, issued to Baziuk, M. in August 1994 describes a boom and pulley system for mounting on the edge of a flat roof. Baziuk, M. does not teach the present invention as claimed.
U.S. Pat. No. 5,265,742 issued to Stenger et al. in November 1993 describes a triangular shaped hoist apparatus attachable to a parapet wall, for lifting objects up and swinging them onto the roof. Stenger et al. do not teach the present invention as claimed.
U.S. Pat. No. 5,203,837 issued to Madic et al. in April 1993 describes a balanced lifting crane. Madic et al. do not teach the present invention as claimed.
U.S. Pat. No. 4,621,741 issued to Boon, C. W. in November 1986 describes a portable roof hoist having a horizontally shifting apex. Boon does not teach the present invention as claimed.
U.S. Pat. No. 4,068,827 issued to Fanning et al. in January 1978 describes a portable S-shaped hoist formed from truss members and having wheels. Fanning et al. do not teach the present invention as claimed.
U.S. Pat. No. 3,978,989 issued to Avila, F., Jr. in September 1976 describes an extensible and collapsible derrick having a roof stand and lateral support provided by a parapet wall. Avila does not teach the present invention as claimed.
U.S. Pat. No. 3,393,906 issued to Duerst, F. in July 1968 describes a hoisting apparatus with a swingable boom and tackle. Duerst does not teach the present invention as claimed.
U.S. Pat. No. 2,623,643 issued to Seamans, J. W. in December 1952 describes a scaffold raiser and remover that clamps to the upper edge of a tank and is further supported by an angled brace. Seamans does not teach the present invention as claimed.
U.S. Pat. No. 2,513,403 issued to Dakin, L. F. in July 1950 describes a triangulated T-shaped hoist having a triangular support frame attachable to a short wall. Dakin, L. F. does not teach the present invention as claimed.
U.S. Pat. No. 1,650,656 issued to Sasgen, M. J. in November 1927 describes a semi-portable derrick having a truss-shaped boom, and mountable on a post or column. Sasgen does not teach the present invention as claimed.
U.S. Pat. No. 1,010,530 issued to Taylor, J. L. in December 1911 describes a portable derrick mounted to a column attached top an L-shaped bracket. Taylor does not teach the present invention as claimed.
British Patent No. 221,348 published in September 1924 describes a hand-operated crane. British Patent No. 221,348 does not teach the present invention as claimed.
British Patent No. 661,209 published in November 1951 describes a ship crane having a pole-mounted boom. British Patent No. 661,209 does not teach the present invention as claimed.
PCT Publication No. WO 93/12029 published in June 1993 describes a portable crane for use on a utility truck. PCT Publication No. WO 93/12029 does not teach the present invention as claimed.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus a concrete tilt up panel wall lifting device solving the aforementioned problems is desired.